Align image corners to video corners in Blender VSE
I don't think there is currently a way.

It is an easy task for an addon, so I made one. You can get a copy of it from here, just save the link to disk, then in blenders preferences under addon click Install From File and select the script you just saved. Once enabled you will find a panel in the sequencer properties N with alignment options.

Currently it will align the selected strips to the top, left, bottom or right of the frame. I was just thinking that I could add align to active strip as well as centre, so it may also have those options by the time you see this.